What is the Difference between a Fluorophore and Fluorochrome?


Fluorophore and fluorochrome refer to the same thing. The difference between fluorochrome and fluorophore is that fluorochrome is any of various fluorescent dyes used to stain biological material before microscopic examination while fluorophore is (biochemistry) a molecule or functional group which is capable of fluorescence.

Fluorophores, or fluorochromes, are fluorescent chemical compounds that are capable of absorbing light from a laser and re-emitting the light within a range of wavelengths upon excitation. This property makes them very useful for staining tissues, cells, and other materials in various analytical techniques such as spectroscopy and fluorescent imaging.

Fluorescence is described in terms of excitation and emission. A fluorochrome may be excited by a laser at a defined excitation wavelength, at which time the molecule absorbs light photons. Then, as it returns to its ground state, the fluorochrome emits those photons with less energy and at a longer wavelength. Because the color of the exciting and emitting light is different, they can be separated from one another by using optical filters.


A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator.

Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, i.e., fluorescent imaging and spectroscopy. Fluorescence detection is a sensitive technique because a positive signal is observed against a negative background. Using tandem dyes, a single laser can excite several fluorophores, which are measured by different detectors.

The brightness of a fluorescent molecule depends on two factors: Extinction Coefficient (ε) – how strongly a fluorescent molecule absorbs light at a particular wavelength. Fluorescence Quantum Yield (Φ) – how efficiently the absorbed light is converted into emitted light.


  • Fluorophores have particular importance in the field of biochemistry and protein studies. For example: In immunofluorescence but also in cell analysis, immunohistochemistry, and small molecule sensors.

  • Multi-ton scale usages in textile dyeing and optical brighteners in laundry detergents.

  • Advanced cosmetic formulations; safety equipment and clothing.

  • Organic light-emitting diodes (OLED).

  • Fine arts and design (posters and paintings).

  • Synergists for insecticides and experimental drugs.

  • As a dye in highlighters to give off a glow-like effect.

  • Solar panels to collect more light / wavelengths.

  • Fluorescent sea dye is used to help airborne search and rescue teams locate objects in the water.


Fluorochromes are selected based on their abilities to fluoresce with the wavelengths of light produced by the lasers. For any given fluorochrome, this will yield an emission spectrum that is different from its absorption spectrum and the disparity between their maximum values is referred to as a ‘Stokes shift.’

Each fluorochrome's stokes shift will vary as a function of its chemical characteristics and the efficiency with which the molecule fluoresces. Any of various fluorescent dyes used to stain biological material before microscopic examination. Any of various fluorescent substances used in fluorescence microscopy to stain specimens.

A chemical that fluoresces, especially one used as a label in biological research. The light emitted by the fluorochrome is then filtered so that each sensor will detect fluorescence only within the filter's range. This fluorescence is the read-out signal provided by the instrument. Fluorochromes used in flow cytometry are essentially those that can attach in some way to biologically significant molecules and are excitable by the lasers commonly found on commercial flow cytometers.


A chromophore is a part of a molecule responsible for its color. The excitation wavelengths can be in the UV to the visible range. Chromophore undergoes a conformational change as occurs in the fluorophore and the returning to the ground state results in emission of the color. This type of chromophores includes food colorings, pH indicators, fabric dyes, carotenoids, etc.

Relation between Chromophore and Fluorophore

The main difference between fluorophore and chromophore is that fluorophore is a part of a molecule, re-emitting the absorbed photon at a longer wavelength whereas chromophore is a part of a molecule, absorbing UV, or visible light to emit light in the visible region. A fluorophore is a fluorescent chemical compound that can re-emit light upon excitations that occur due to a light source. Chromophore is a part of a molecule that is responsible for the color of that molecule.


A fluorophore is a part of a molecule that can absorb light ranging from UV to blue light, emitting the light in higher wavelengths. In contrast, a chromophore is another part of molecules that can absorb light from UV to the visible range, emitting the light in the visible range. Therefore, a fluorophore emits fluorescence while a chromophore is responsible for the color of the molecule. The main difference between fluorophore and chromophore is the wavelengths emitted.

Updated on: 18-May-2023


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